From a52ab2afbf38e42376732d41b14279fd29fcf23f Mon Sep 17 00:00:00 2001
From: Marco Costalba <mcostalba@gmail.com>
Date: Sat, 18 Apr 2009 16:21:44 +0100
Subject: [PATCH] Micro optimize generate_piece_checks()

Avoid calculating piece attacks if there aren't
available check sqaures for the given piece.

About 15% of cases. Not a biggie but still something
especially in the middle game where king is well covered
inside his castle.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---
 src/movegen.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/movegen.cpp b/src/movegen.cpp
index 0f2f6b4e..d2b55bd2 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -815,6 +815,9 @@ namespace {
         return mlist;
 
     Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
+    if (!checkSqs)
+        return mlist;
+
     while (b)
     {
         Square from = pop_1st_bit(&b);
-- 
2.39.2